This data set contains 4-band (natural color plus infrared) imagery from the National Agricultural Imagery Program (NAIP). NAIP acquires digital ortho imagery during the agricultural growing seasons in the continental U.S. A primary goal of the NAIP program is to enable availability of ortho imagery within one year of acquisition. The source files are 1 meter ground sample distance (GSD) ortho imagery rectified to a horizontal accuracy of within +/- 5 meters of reference digital ortho quarter quads (DOQQ's) from the National Digital Ortho Program (NDOP) or from NAIP. The tiling format of NAIP imagery is based on a 3.75' x 3.75' quarter quadrangle with a 300 meter buffer on all four sides. NAIP quarter quads are formatted to the UTM coordinate system using NAD83. NAIP imagery may contain as much as 10% cloud cover per tile. This file was generated by compressing NAIP quarter quadrangle tiles that cover a county. JPEG2000 compression was used. Target values for the compression ratio are (15:1). (Note: MnGeo has created this metadata record to describe the entire NAIP2008 dataset, using information from Farm Service Agency metadata. Each county file is accompanied by the original FSA metadata for that county.) The downloadable shapefile represents a statewide quarter-quadrangle tile index that indicates the date that each image was flown.

Purpose

NAIP imagery is available for distribution within 60 days of the end of a flying season and is intended to provide current information of agricultural conditions in support of USDA farm programs. For USDA Farm Service Agency, the 1 meter GSD product provides an ortho image base for Common Land Unit boundaries and other data sets. The 1 meter NAIP imagery is generally acquired in projects covering full states in cooperation with state government and other federal agencies who use the imagery for a variety of purposes including land use planning and natural resource assessment. With an annual cycle, NAIP is also used for disaster response often providing the most current pre-event imagery.

Time Period of Content Date

2008

Currentness Reference

May through September 2008. The downloadable shapefile represents a statewide quarter-quadrangle tile index that indicates the date that each image was flown. For the county downloads, see the accompanying quarter-quad boundary shapefile for each county to find out the date(s) that the source imagery was acquired.

The Aerial Photography Field Office asks to be credited in derived products.

Imagery may be replaced to address defects found in a small number of products through quality assurance processes. Imagery containing defects that require the acquisition of new imagery, such as excessive cloud cover, specular reflectance, etc., will not be replaced within a NAIP project year.

MnGeo Redistribution conditions: In obtaining this data from MnGeo, it is understood that you and/or your organization have the right to use it for any purpose. If you modify it, you are encouraged to apply responsible best practices by documenting those changes in a metadata record. If you transmit or provide the data to another user, it is your responsibility to provide appropriate content, limitation, warranty and liability information as you see fit.

A shapefile, with its associated metadata, is included with this dataset. It shows polygons delineating the boundary between DOQQ imagery used in the creation of the county NAIP file and attributes such as the source date of the imagery.

FSA Digital Orthophoto Specs. The quarter-quad files are 1 meter ground sample distance (GSD) ortho imagery rectified to a horizontal accuracy of within 5 meters of reference digital ortho quarter quads (DOQQ's) from the National Digital Ortho Program (NDOP) or from NAIP.

Vertical Positional Accuracy

N/A

Lineage

This Compressed County Mosaic was generated to JPEG 2000 (jp2) specifications using a target compression ratio of 15:1. All photography was acquired using digital mapping cameras and accompanied by the collection of airborne Global Positioning System (GPS) data. Orthorectification was performed with custom software and the USGS National Elevation Dataset was used for the elevation model. Digital orthophotos were radiometrically balanced in groups of 100-500 images using the Inpho OrthoVista product. Custom software automatically generated the jp2 project parameter file to control the insertion of the digital orthophotos in the final mosaic. The ordering scheme of the digital orthophotos is based on a last-in-last-on-top scheme.

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